This invention pertains to the art of cable closure assemblies and more particularly to a closure assembly which encloses a fiber optic cable splice or the like and prevents the ingress of moisture.
The invention is particularly applicable to an encapsulated fiber optic closure assembly, and a method of encapsulating a fiber optic cable, and will be described with particular reference thereto. However, it will be appreciated that the invention has broader implications and may be advantageously employed in other closure assembly ennvironments and applications.
Use of closure assemblies for splice cases, cable vaults, and other eletrical cable terminus receiving containers are well known in the art. Although some of these prior constructions are suitable for the recent advent and changeover to fiber optic technology, certain other parameters and qualitative requirements must be met to fully incorporate all aspects of the fiber optic technology. The fragile nature of the individual optical fibers requires special handling and care to prevent any damage, undue compression, or breakage. Further, the splice area must be kept clean and free of moisture so that the transmissibility through the cable remains unaffected and any alteration of the signal carrying capabilities of the cable is minimized.
Prior arrangements utilized by others have simply field constructed or custom-made an individual unit around a fiber optic cable tray organizer. Although these closure assemblies have met with some or limited success, this piecemeal approach for a construction that is being encountered more and more frequently requires vast improvement. In fact, the prior arrangements can only be considered as meeting the minimum criteria for simplicity, reliability, and repeatability.
Further, the custom-made closure assemblies still have problems associated with moisture ingress into the interior cavity which receives the spliced cables. Previous designs have utilized air pressure or other gaseous pressure in an effort to limit the ingress of moisture. It has been considered desirable to add an additional or further blanket of protection to the cable splice area.
Although other non-optical fiber cable closure assemblies have adequately incorporated resin type seal arrangements into their structures in an effort to alleviate the moisture ingress problem, these structures have completely encapsulated the cable splice connections, i.e., completely filled the central cavity with the resin material. As referenced above, the fiber optic cables require special treatment and the applicability of these resinous arrangements remains in doubt due to the generally held view that use of resin is incompatible with the fiber optic cable splice technology.
The present invention is deemed to meet the foregoing needs and others in a manner that provides an extra protective layer through limited use of resin. Simultaneously, the closure assembly is so constructed that the exposed optical fibers in the splice cavity remain free and unaffected by use of the resin.